N-homolupinanoyl and N-(omega-lupinylthio)alkanoyl derivatives of some tricyclic systems as ligands for muscarinic M1 and M2 receptor subtypes.

A set of N-homolupinanoyl- and N-(omega-lupinylthio)alkanoyl derivatives of tricyclic systems (as phenothiazine, iminodibenzyl and dihydropyridobenzodiazepinone) has been prepared and tested for affinity for rat muscarinic M(1) and M(2) receptor subtypes labeled with [3H]pirenzepine and [3H]AF-DX 384. Good affinity for both M(1) and M(2) subtypes was displayed by most compounds, often with nanomolar K(i) values, which for lupinylthiopropionyl- and lupinylthiobutyryl-phenothiazines (13-16) were comparable to those of pirenzepine and methoctramine, respectively. However, only moderate selectivity for one or the other subtype was seen.